HomeMy WebLinkAbout2007 09 24 Informational 101 Noise Data Collection Seminole Expressway
COMMISSION AGENDA
ITEM 101
CONSENT
INFORMATIONAL X
PUBLIC HEARING
REGULAR
September 24, 2007
Meeting
IY/
f, MGR / Y /DEPT
Authorization
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REQUEST: Public Works Department providing the City Commission with information
regarding the City's independent noise data collection on the Seminole
Expressway (SR 417)
PURPOSE: The purpose of this agenda item is to provide the City Commission with
information regarding the City's independent noise data collection on the
Seminole Expressway (SR 417)
ISSUE OVERVIEW:
. Florida's Turnpike recently completed a Project Development and Environment (PD&E)
Study for the proposed widening of the Seminole Expressway (SR 417) from 4-lanes to
8-lanes from the Orange/Seminole County line to the Rinehart Road interchange.
. A Noise Study was completed as a part of the PD&E Study by the Turnpike's engineering
consultant, PBS&J. The Noise Study concluded that a noise barrier was not a reasonable
abatement measure in Winter Springs where the Expressway borders Chelsea Woods,
Chestnut Estates, and Seneca Bend (an Oviedo subdivision) because the cost per
benefited residence exceeds the $35,000 upper limit established by FDOT.
. In June 2007, the City hired Dr. John MacDonald to perform a technical review of the
noise impact component of the Turnpike's PD&E report. Dr. Macdonald reviewed the
study mcthodology and the abatement options that were considered, including the
estimation of the number of benefited receivers and a review of the reasonableness
criteria used to detennine whether noise abatement is appropriate. Dr. Macdonald also
reviewed the Turnpike's Traffic Noise Model used to predict sound levels and noise
banier impacts.
. The City Commission received Dr. MacDonald's evaluation report as an informational
agenda item at the August 13,2007 Commission meeting. The Commission directed
Informational Agenda Item 101
September 24,2007
Page 2 of3
Staff to proceed with noise data collection to verify the Turnpike's noise model
calibration.
NOISE DATA COLLECTION SUMMARY:
Dr. John MacDonald monitored sound pressure levels on September 5, 2007 at two locations
along the Seminole Expressway. The fIrst location was in Chelsea Woods at Otisco Way, a
location shown in the Turnpike's Noise Study to be one of the most severely impacted areas in
Winter Springs. The second location was at Mikler Road, which is the same location the
Turnpike used to collect noise data to calibrate the noise model. The Mikler Road location is in
Seminole County, approximately halfway between Red Bug Lake Road and Aloma A venue.
At both monitoring locations, sound levels were monitored for approximately eight hours,
including portions of the morning and evening peak traffic periods. Trat1ic and meteorological
data was also collected throughout the eight hour period. Dr. MacDonald's noise data collection
procedures complied with the applicable FOOT guidelines.
A copy of Or. MacDonald's Draft Report is attached as Exhibit A. Some key summary points
from the noise data collection are as follows:
. The measured sound levels at Mikler Road were consistent with the Turnpike's measured
sound levels at the same location for the same time period (approximately 11 :00 AM).
. Sound levels during the peak traffic periods were measured to be up to 5 dBA higher than
the off-peak periods at both monitoring locations.
. Sound levels measured at Otisco Way in Chelsea Woods were generally consistent with
those at Mikler Road throughout the measurement period.
FDOT SOUND WALL DECISION CRITERIA:
The Turnpike utilizes a two-step process to detennine if a noise barrier is a reasonable abatement
measure for a particular area:
. STEP 1 - Is the area impacted?
The minimum noise level for a residence to be considered impacted is 66 dBA. The
Turnpike's Noise Study concluded that residences in Chelsea Woods, Chestnut Estates,
and Seneca Bend will be impacted. After an area has been dctennined to be impacted,
the decision on whether noise abatement is reasonable advances to Step 2. In the case of
Chelsea Woods, Chestnut Estates, and Seneca Bend, no additional noise data collection
or analysis is necessary regarding the number of impacted residences, or the severity of
the noise impacts, because the area has already been determined to be impacted.
Informational Agenda Item 101
September 24, 2007
Page 3 of3
. STEP 2 - If the area is impacted, are there enough benefited receivers such that the
cost of a noise barrier does not exceed $35,000 per benefited receiver?
A benefited receiver is defined as a site that would experience at least a 5 dBA noise
reduction as a result of providing a noise barrier. The Turnpike's Noise Study concluded
that 45 residences in Chelsea Woods, Chestnut Estates, and Seneca Bend would receive
at least a 5 dBA reduction and therefore qualify as benefited receivers. The cost of a
noise barrier per benefited receiver for the impacted residences is $48,636, which exceeds
the $35,000 maximum specified by the FOOT's noise study manual. In this case, a total
of 64 benefited receivers would be needed to be within the maximum cost criteria.
Typically, only the homes within the first few rows of the highway will experience a 5
dBA or greater noise reduction when a noise barrier is installed. Therefore, the density of
the residences closest to the highway is a critical factor in determining the number of
benefited receivers.
ADDITIONAL INFORMATION:
Representatives from the Turnpike met with homeowners from Chelsea Woods, Chestnut
Estates, and Seneca Bend on September 17,2007 to discuss the noise barrier issue.
Approximately 90 residents attended the meeting. The Turnpike gave a brief presentation and
then answered questions and listened to comments from the residents. All residents attending the
meeting expressed a desire to have a noise barrier installed. The Turnpike reiterated their
position that the area is impacted by noise, but the cost per benefited receiver exceeds the
maximum allowed under FDOT criteria. The Turnpike agreed that the noise study would be re-
perfonned at the design stage of the 8-lane widening project, which has not been programmed for
funding at this time.
FUNDING:
The City has spent a total of $3,585 to-date for Dr. John MacDonald's services, consisting of
$1,235 for the technical review of the Turnpike's Noise Study, and $2,350 for the collection and
evaluation of noise data.
A TT ACHMENTS:
1. Exhibit A - Sound Level Measurements of the SR 417 Corridor
COMMISSION ACTION:
Sound level Measurements of the
S.R. 417 Corridor
Draft Report
Prepared for:
Brian Fields
City Engineer
City of Winter Springs
1126 East S.R. 434
Winter Springs, Florida 32708
Prepared by:
John M. MacDonald, Ph.D., P.E.
3142 Ash Park Loop
Winter Park, Florida 32792
September 7, 2007
,4
Draft Sound Level Report, J. MacDonald, PE, LLC
Seminole Expressway (S.R. 417) Sound Pressure Levels
September 7, 2007
Introduction
The following report summarizes the results of environmental sound pressure level
testing that occurred along the Seminole Expressway in the vicinity of Winter Springs,
Florida. Sound pressure levels were monitored at two locations along the corridor
between Aloma Avenue and S.R. 434 and in the vicinity of residences that border this
roadway. The sampling took place on September 5,2007. The purpose of the sound level
survey was to ascertain existing sound pressure levels caused by the Seminole
Expressway in the course of a given day from morning rush hour to evening rush hour.
Meteorological data was also collected to ensure that weather conditions did not exceed
acceptable levels for sound level monitoring in accordance with ANSI guidelinesl.
Methodology
Sound level analyzers were positioned at two locations along the S.R. 417 corridor
between Aloma Avenue and S.R. 434 to monitor sound pressure levels over an eight hour
period. Type I sound level analyzers were used in this test (Cesva SC31 0) and were
calibrated (Rion model NC-74 calibrator) and operated in accordance with FDOT and
ANSIl guidelines including the use of windscreens. The analyzers measured one second
Leq sound pressure levels for the duration of the measurement period. This data was
used to compute hourly Leq levels for the eight hour time period.
A technician was located at the measurement locations for the purpose of identifying
sound sources other than the highway during the measurement period. These observer
logs were used during data analysis to determine the source of specific loud acoustic
events and to remove extraneous events such as commercial jet flyovers and resident
noise from the data.
Figure 1 depicts the S.R. 417 corridor and the measurement locations at Otisco Way west
of the highway located in the Tuskawilla Communities area of Winter Springs and Mikler
Road located east of the highway and near Aloma Avenue.
I ANSI S1.13-1971 (1986), American National Standard, Methods/or the Measurement o/Sound
Pressure Levels
2 The units are decibels (dB) and the descriptor (A) after dB indicates that the sound frequency
bands have been weighted to simulate the response of the human ear. The descriptor Leq, is an
acoustic average of the sound energy during a specified time period that represents the same
acoustic energy as the time-varying value. Meters were set to a Slow time constant for
exponential averaging. The acoustic signal is sampled 8 times per second and Lmax is the
maximum sound pressure level within the 8 samples (assuming a one second sample rate).
Draft Sound Level Report, J. MacDonald, PE, LLC
2
Figure 1. Aerial of S.R. 417 and Measurement Locations.
Table 1 summarizes the sound level analyzer locations, their distances from the ROW
and from the S.R. 417 nearest travel lane. Table 1 also contains the calibration levels of
each analyzer and the start and end of the test period.
Table 1. Measurement Locations.
Location
Distance from
nearest S.R. 417
travel lane
Sound Level
Analyzer
SOT*
calibration
level dB(A)
EOT*
calibration level
dB(A)
Mikler Road,
100 ft. from
ROW fence
Mikler Road,
150 ft. from
ROW fence
Otisco Way,
100 ft. from
ROW fence
*SOT = start of test; EOT = end of test
190 ft.
Cesva
SN:T219972
SN :T220281
Cesva
SN :T219965
94.0
94.0
93.8
94.0
240 ft.
94.0
93.8
182 ft.
Cesva
SN:T220278
94.0
94.0
Draft Sound Level Report, J. MacDonald, PE, LLC
3
Recorded data was adjusted for calibration drift using the pre-event and post-event
calibration levels noted in Table 1 (cal adjustment = {2*SPLret~SPLsorSPLEOT}/2). The
analyzers measured one second Leq sound pressure levels for the duration of the
measurement period.
Meteorological conditions were monitored and recorded (at the Mikler Road location) to
ensure that sound level data were collected under acceptable conditions. Data was not
included in the analysis if wind speeds exceeded 5 m/sec. Winds were low throughout
the test but there was intermittent rain that occurred at the Mikler Road location.
Equipment was covered during rain events and calibration levels were checked to ensure
that humidity was not causing adverse effects on the sound level analyzers and
microphone/preamp systems. Appendix A contains meteorological information collected
during the measurements.
Measurement Results
Sound pressure levels were recorded from 7:30 a.m. to 4:30 p.m. on September 5, 2007.
Figures 2-4 are the time histories of the one second Leq sound pressure levels at each
location. A rain event occurred at Mikler Road from 1:48 p.m. to 2:01 p.m. and again at
4: 15 p.m. which ended the test at the Mikler location. No rain events occurred at the
Otisco Way site.
100 ft. from ROW fenceline-Mikler Rd.
;:t
in
"0
,3
<I>
'"
85
80
75
70
65
60
55
50
,p ,p ,p ,p ,p ,p ~ ,p ,p ,p <<~ <<~ <<~ <<~ <<~ <<~ <<~ <<~ <<~
~ .~ ~ .~ ~ ~ ~ ~ ~ ~ ~ ~ ~ .~ ~ ~ .~ ~ .~
.~~~~$Pfl#~~~~~~~~~~~
, v v ~, ~, "v "v "C). "". "". ,,'1,. ,,'1,. ". ". '1,. '1,. "0. "0. ~.
----~
Figure 2. Sound Pressure Level time history at Mikler Road, 100 f1. from ROW
fcneeline.
Draft Sound Level Report, J. MacDonald, PE, LLC
4
150 ft, from ROW fenceline-Mikler Rd. Sept. 5,2007
85
80
<( 75
00
"0 70
g 65
VI 60 .
55
50
~~~~~~~~~~~~~~~~~~~~
~,~~~~~~~~~~~~~~~~~~,~
'1,-' '0' Rl' 'b ~, '0' lx' ~' (\,' ", Rl' '0' ,.:\' '0 5:)' Ix (\, " ,5:) Q>
,," ,,~ qjG '0'" d.J'0 d.J~ "c::)\:! "c::)'? <,'0 ,,"':.> ,,<tG dV ,,<t'.J ",'Y ",Yj 't'V 'j,,~ ".)'!--' ':.>'J Ix",
---.----
Figure 3. Sound Pressure Level time history at Mikler Road, 150ft. from ROW fenceline.
The Mikler Road results (Figures 2 and 3) show that sound pressure levels were generally
louder in the morning rush hours by about 5 dB(A) and then remained constant
(fluctuated about a similar mean value) throughout the day into the afternoon rush time
period. A loud truck event on the highway is noticeable at the 1 :02 p.m. location in
Figures 2 and 3.
-
100 ft, from ROW fenceline-Otisco Way, Sept. 5, 2007
<(
00
"0
U
CII
VI
85
80
75
70
65.
60
55
50
~~~~~~~~~~~~~~~~~~~~
~ ,~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
~~~~~~~~~~~'~.~'~~~~~~~
'\' '\ '0' '0' Q> Q> ~ ~ ~ ~ ~ ~ ~ ~' ~. ~ ~ ':.>' ~ ~'
Figure 4. Sound Pressure Level time history at Otisco Way, 100ft. from ROW fenceline.
The Otisco Way sound levels shown in Figure 4 indicate elevated levels [approximately
64 dB(A)] in the morning rush period, followed by an off-peak period that was about 4
dB(A) less than the morning peak. The sound levels increased again in the afternoon,
corresponding to the beginning of the evening rush time period.
Figure 5 plots the hourly LcqA levels at each site and Table 2 contains displays the LeqA
levels in a tabular fonnat along with the calibration measurements noted in the Draft
PD&E doeumene.
] "Draft Project Development and Environment Noise Study Report, Widening Seminole
Expressway (SR 417) from South of Aloma Avenue to the Rinehart Road Interchange",
Seminole County, Florida, Financial Project 10#417545-1, April 2007.
Draft Sound Level Report, J. MacDonald, PE, LLC
5
Hourly Leq Values on 417 Corridor
Sept. 5, 2007
70
~
III 60
"0
65
-- Otisc~W~y~ L~qAhr "I
Mikler. 100 ft.. LeqAhr
-Mikler. 150 ft.. LeqAhr;
50
<0'0'0 ,\'0'0 ro'0'0 0;;'0'0 ,,'0'0'0 ",,'0'0 <j,,'0'0 <,:>'0'0 ,,">-'0'0 ,,<0'0'0 ,,<0'0'0 .:?'0 "ro'0'0
hour (1600 = 1600-1659)
Figure 5. Hourly LeqA results from the measurement locations.
Table 2. Hourly LeqA Measurements from this data collection effort and the results listed
in the Draft PD&E document.
Table 2 indicates that the measurements conducted on September 5, 2007 are similar to
those measurements taken in March of this year (listed in the Draft PD&E). The Leq for
the entire 11 :00 am hour on September 5,2007 (at the Mikler Road, 100 ft. location) was
61.1 dB(A) while the 10 minute readings from March 29,2007 were between 61.4 and
61.7 dB(A). This indicates that the 10 minute samples were a fairly accurate estimate for
Draft Sound Level Report, J. MacDonald, PE, LLC
6
the full hour Leg. The Sept. 5, 2007 hourly measurements at the 150 ft. Mikler location
were within 1 dB(A) of those reported in the Draft PD&E.
Total traffic counts (sum of traffic in both directions) of S.R. 417 were manually taken by
the observer at the Mikler Road location and Traffic speeds were estimated by "drive-
thrus" of the corridor at various times during the day. Tables 3 and 4 detail those
measurements. Figure 6 displays the traffic counts graphically and depicts the morning
and afternoon increased traffic levels that were indicated in the time history graphs.
Hourly S.R. 417 Estimates based on manual counts
Vl
!:
o 5000
:;::l
u
~ 4000.
"C
~ 3000
.0
~ 2000
o
~
Ui 1 000
C1l
U
~
C1l
>
0
.t .t .t .t <(~ <(~ <(~ <(~ <(~
.'0'0 .'0'0 .'0'0 '0'0 .'0'0 .'0'0 '0'0 .'0'0 .'0'0
'1". ~. co. '0 $:). '1" .<f. co. '0
'\" <0')) 0.)":5 \St>- .\:) ." 'S":5 ~t>-
"'1,, ". '1"
~
Figure 6. Graph of Total Traffic (both directions, all lanes) counts on S.R. 417, Sept. 5,
2007.
Draft Sound Level Report, J. MacDonald, PE, LLC
7
Conclusions
This report has summarized the results of environmental sound pressure level testing that
occurred along the Seminole Expressway (S.R. 417) in the vicinity of Winter Springs,
Florida. Sound pressure levels were monitored at two locations along the corridor
between Aloma A venue and S.R. 434 and in the vicinity of residences that border this
roadway. The sampling took place on September 5, 2007. These measurements were
conducted between 7: 12 a.m. and 4:30 p.m. Table 5 summarizes the findings of peak and
off-peak hourly sound pressure levels (Leg) at these measurement locations.
Table 5. Peak and off-peak sound levels at two geographic locations on the S.R. 417
Corridor Se 1. 5, 2007 .
Otisco Way, 100 f1.
from ROW
I fence line
64 dB(A)
61 dB(A)
63 dB(A)
These measurements were compared to those reported in the Draft PD&E Noise Study
conducted as part of a widening project of this roadway. The reported sound pressure
levels in the Draft PD&E were within 1 dB(A) of the measured hourly levels conducted
during this work. The measurements listed in the Draft PD&E were conducted during
anoff-peak time period (11 :08 to 11 :33 a.m.). This report demonstrated an approximate 5
dB(A) difference between morning Leg levels and the off-peak levels (hourly Leg). The
sound levels began to increase in the afternoon and showed a similar p.m. msh hour
trend. The measurements were scheduled to end at 4:30 p.m. but the Mikler Road
location experienced rain at 4: 15 p.m. which ended the test at Mikler Road. Otisco Way
measurements continued until 4:30 p.m.
Draft Sound Level Report, J. MacDonald, PE, LLC
to)
Q)
~
E
Appendix A
Weather Data
Wind Conditions at Mikler Road, Sept. 5, 2007
6
5
4
3
2
1
o
~ ~ ~ '?-~
".'0'0 ",?'0'0 .'0'0
.v v< <0' 'b'
~~ ~~ ~~ ~~
"
~~ ~~ ~~ ~~ ~~
'0'0 '0'0'0'0 '0'0 .'0'0
.'0'0~'t.~. .";}<o ",1>:.'0'
~'t ~. 't. ";}. v<
l~uw~n_d~~~ed, ~~sJ
8
Draft Sound Level Report, J. MacDonald, PE, LLC
9